Sniffer Robot With Infotaxis Algorithms On The Hunt

Is it possible for a robot to follow a scent? Massimo Vergassola and his colleagues at the Pasteur Institute in Paris, France think so. They have derived a new algorithm using a method they call "infotaxis" that is similar to the strategy employed by moths.

The simplest approach to locating the source of an odor is chemotaxis - moving in the direction of higher concentration. This doesn't work for large animals in turbulent air flows; the odor plume is not smoothly consistent from low concentration to higher concentration. A more sophisticated method is needed.

Locating the source of odor in a turbulent environment—a common behavior for living organisms—is nontrivial because of the random nature of mixing. Here we analyze the statistical physics aspects of the problem and propose an efficient strategy for olfactory search that can work in turbulent plumes. The algorithm combines the maximum likelihood inference of the source position with an active search. Our approach provides the theoretical basis for the design of olfactory robots...

Moths employ two distinct methods; "zigzagging" upwind when they have the scent, then "casting," which is moving crosswind to try to relocate the interrupted scent trail.

Robots could do the same thing, now that the math has been worked out.

Science fiction writers have long thought about robots with a sense of smell. In his classic 1953 novel Fahrenheit 451, Ray Bradbury created the chilling mechanical hound that guarded the fire station:

The mechanical Hound slept but did not sleep, lived but did not live in its gently humming, gently vibrating, softly illuminated kennel...

Nights when things got dull, which was every night, the men slid down the brass poles, and set the ticking combinations of the olfactory system of the hound and let loose rats in the fire house area-way. Three seconds later the game was done...
(Read more about Ray Bradbury's mechanical hound)

Another attempt to visualize sniffer robots and assign them a practical task is found in the 1985 movie Runaway by Michael Crichton. In the film, detectives use a four-legged sniffer robot to find and identify trace compounds at a crime scene (see Crichton's sniffer robot from Runaway).

Robots are already in the testing stage who are able to detect odors and perform relevant actions. The RI-MAN health care robot has a smell-discernment capability, used to detect an incontinent patient. Other research includes the SPOT-NOSED nanobiosensors under development in the European Union.